The nation's weather

WEATHER UNDERGROUND

Sep. 08, 2015

A cold front will stretch from northern New England to the Intermountain West on Tuesday, while a stormy pattern persists across the Southeast.

A cold frontal boundary will extend southwestward across northern New England, the Great Lakes, the upper Mississippi Valley, the central Plains and the central Rockies. As this frontal boundary transitions southeastward, rain and thunderstorms will develop over New England, the northern Mid-Atlantic, the Midwest, the Mississippi Valley, the central Plains and the southern Plains. The heaviest rain will likely develop over the Plains and the middle Mississippi Valley, which will bring threats of flash flooding to eastern Oklahoma, southeast Kansas, northwest Arkansas, Missouri, southeast Iowa and northern Illinois.

Meanwhile, an area of low pressure will drift southwestward over the Deep South and the Gulf of Mexico. This area of low pressure will generate showers and thunderstorms across the Gulf Coast, the Southeast and the southern Mid-Atlantic on Tuesday.

Out west, monsoonal moisture and daytime heating will aid in the development of showers and thunderstorms across the southern and central Rockies, as well as portions of the Desert Southwest. Additionally, an onshore flow from the Pacific will bring chances of light to moderate rain to the northern tier of the Pacific Northwest. There will be a slight chance of afternoon thunderstorms over the northern Rockies.

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Temperatures in the Lower 48 states Monday have ranged from a morning low of 19 degrees at West Yellowstone, Mont. to a high of 104 degrees at Alva, Okla.